Term
| In the vast majority of cases, catecholamines have ______ functions |
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Definition
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Term
| 5 types of monoamine transmitters |
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Definition
1. dopamine (DA)
2. norepinephrine (NE, AKA noradrenaline)
3. epinephrine (EPI, AKA adrenaline)
4. serotonin (5-HT)
5. histamines |
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Term
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Definition
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Term
| Catecholamines work largely in a ______ fashion in the CNS |
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Definition
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Term
| Do catecholamines have wide or small projections from the cell body? |
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Definition
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Term
| When catecholamine brainstem areas become active --> ? |
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Definition
| overall brain activity levels are affected |
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Term
| _____ neurons act more in the periphery (not as much around the brain) |
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Definition
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Term
| Are catecholamines primarily inhibitory or excitatory? |
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Definition
| actions are actually all over the board if they're inhibitory or excitatory |
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Term
| NE going form locus coeruleus in the brainstem --> ? |
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Definition
| pyramidal cells in the hippocampus |
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Term
| 5 steps of NE in the beta-adrenergic receptor in the hippocampus (responsible for a lot of the after-hyperpolarization phase of the action potential [AHP dip]) |
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Definition
1. NE binds
2. activates adenyl cyclase
3. cAMP
4. PKA
5. affects calcium-dependent potassium channel |
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Term
| No NE on the beta-adrenergic receptors in the hippocampus (control): continued stimulus --> ? |
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Definition
| action potentials at a slower rate |
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Term
| NE application on the beta-adrenergic receptors in the hippocampus: continued stimulus --> ? |
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Definition
| much faster rate of firing of action potentials over & over again (virtually no AHP dip) |
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Term
| Increase of locus coeruleus activity (NE) --> ? |
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Definition
| increase of Hz of action potentials |
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Term
| Why does application of NE to the beta-adrenergic hippocampal receptors cause a faster rate of action potential firing? |
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Definition
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Term
| common precursor for all catecholamines |
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Definition
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Term
| 4 steps to make all catecholamines |
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Definition
1. tyrosine --> (via TH enzyme) --> L-DOPA
2. L-DOPA --> (via AAAD enzyme) --> DA
3. DA --> (via DBH enzyme) --> NE
4. NE --> (via PNMT enzyme) --> EPI |
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Term
tyrosine --> (via "tyrosine hydroxylase" [TH] enzyme) --> L-DOPA
*where does this happen?* |
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Definition
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Term
| Is tyrosine hydroxylase (TH) unique to catecholamine-containing neurons? |
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Definition
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Term
| What is the first unique enzyme in the catecholamine synthesis pathway? |
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Definition
| tyrosine hydroxylase (TH) |
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Term
| 3 co-factors required for tyrosine hydroxylase (TH) |
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Definition
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Term
L-DOPA --> (via AAAD enzyme) --> DA
*where does this occur?* |
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Definition
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Term
| Is AAAD (aromatic amino acid decarboxylase) enzyme good for labeling DA neurons? |
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Definition
| no! (it is a ubiquitous enzyme) |
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Term
| How is DA packaged into vesicles? |
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Definition
| VMAT (vesicular monoamine transporter) |
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Term
| Where does DA --> (via dopamine beta-hydroxylase) --> NE happen? |
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Definition
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Term
| 2 neurons that dopamine beta-hydroxylase is unique to |
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Definition
1. NE
2. EPI
*not found in DA neurons* |
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Term
| How does NE get transported out of the vesicle to be turned into EPI? |
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Definition
| VMAT (same transporter as with dopamine!) |
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Term
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Definition
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Term
| What determines how far along the catecholamine synthesis pathway a neuron gets? |
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Definition
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Term
| Catecholamine synthesis is regulated via a ______ feedback loop |
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Definition
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Term
| Describe the negative feedback loop for catecholamine synthesis regulation |
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Definition
| when there is a lot of one of the neurotransmitters (DA, EPI, or NE), it will feedback to the TH & downregulate its activity |
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Term
| What experiment proved the negative feedback loop for catecholamine synthesis regulation? |
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Definition
1. put tyrosine & TH in a test tube --> L-DOPA
2. put tyrosine & TH & DA, NE, or EPI --> nothing! |
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Term
| What is key for catecholamine synthesis regulation? |
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Definition
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Term
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Definition
enzyme that breaks down catecholamines (monoamines)
*located both intracellularly & extracellularly* |
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Term
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Definition
enzyme that breaks down catecholamines
*only extracellular* |
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Term
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Definition
| transporter that brings dopamine back into the presynaptic terminal |
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Term
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Definition
| transporter that brings NE or EPI back into the presynaptic terminal |
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Term
| Many inhibitors of monoamine transporters are ______ drugs |
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Definition
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Term
| Psychoactive drugs mainly affect catecholamine levels via ______ |
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Definition
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Term
presence of cocaine = build-up of DA in the synaptic cleft --> larger & longer-lasting DA spike
why? |
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Definition
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Term
presence of amphetamine = even bigger, longer DA spike than cocaine
why? |
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Definition
| blocks DAT but also goes backwards through DAT to get into the presynaptic terminal to block VMAT |
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Term
| MPTP & the frozen addicts |
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Definition
| people coming into doctors with Parkinson's-like symptoms coming on very quickly |
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Term
| the frozen addicts were _____ addicts |
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Definition
| heroin (but whoever made their heroin made it wrong) |
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Term
| MAO turns MPTP into --> ? |
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Definition
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Term
| How quickly did the frozen addicts develop their symptoms |
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Definition
| within days of taking the drug |
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Term
| Parkinson's Disease is a chronic & progressive _____ disorder |
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Definition
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Term
| Parkinson's Disease primarily affects the ______ |
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Definition
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Term
| 4 main symptoms of Parkinson's Disease |
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Definition
1. tremor
2. bradykinesia
3. rigidity
4. change in speech |
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Term
| Do Parkinson's Disease treatments vary from person to person? |
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Definition
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Term
| Main goal of Parkinson's Disease treatment: ? |
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Definition
| target DA receptors or alter the amount of DA present |
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Term
| What is the benefit of using L-DOPA to treat Parkinson's Disease? |
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Definition
| can cross the BBB & be converted into DA |
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Term
| Are DA agonists as effective of a treatment for Parkinson's Disease as L-DOPA? |
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Definition
| no but the effects last longer |
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Term
| 2 enzymes inhibited in Parkinson's Disease treatment |
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Definition
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Term
| What do anticholinergics do to treat Parkinson's Disease? |
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Definition
| block mAChR to stop resting tremor |
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Term
| What does dopamine do in the motor signaling? |
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Definition
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Term
| About _____% of Parkinson's patients develop the disease due to treatment with a specific medication |
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Definition
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Term
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Definition
| get urge to do normal human behavior but do it in excess |
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Term
| Do people with impulsivity disorders know that what they're doing is wrong? |
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Definition
| yes, but they still do it anyway |
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Term
| impulse control disorders (ICDs) |
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Definition
| behavioral disturbance resulting from the failure to resist the drive to behave in ways that result in distress or impaired social & occupational functioning |
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Term
| What is the main treatment for impulsivity disorders? |
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Definition
| reduce or stop using the suspected agent (especially DA agonists) |
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